There are many known types of apparatus for converting thermoplastic or so-called "hot melt" materials from a solid state to a molten liquid state. The melted material was maintained in the molten state in the tank in sufficient volume to supply one or more applicators or dispensers. A number of design improvements were made over a period of time to provide greater efficiency of the melt tanks and reduce problems of charring or oxidation of the molten material due to the material being maintained in the molten state for a prolonged period of time.
A grid type hot melt applicator was designed to have the capability of melting a very high throughput of thermoplastic material in a very short time so that the molten material was not maintained in a molten state for prolonged periods of time which could result in degradation of the material. A typical grid type applicator is disclosed in U.S. Pat. No. 3,964,645. Other examples are shown in U.S. Pat. Nos. 3,981,416, 4,474,311, 4,667,850, and 4,821,922. Continued efforts to improve melter apparatus has resulted in the present invention.